Orthopedic surgeons and physical therapists often use traction to treat traumas affecting a part of body's bone structure.
For instance, traction may be applied to a leg in order to realign a broken femur bringing the two fractioned interfaces together so that they can be rejoined. Traction may also be used to lengthen a limb that has atrophied as a result of a degenerative muscular disorder such as poliomyelitis. In such a case, the femur is sewed into two sections and traction is applied to the leg to bring the two severed sections into close proximity and letting the natural regrowth of the bone feel the traction-induced gap.
Traction is typically applied over a long period of time with progressive increase of the traction force. Accordingly, orthopedic traction requires a careful control of that force. This is commonly achieved by use of weights dangling from a string passing over a pulley and attached at the other end to the patient's limb. Weights can be progressively added or removed to adjust the traction force. An example of this type of traction equipment is disclosed in U.S. Pat. No. 4,653,482 Kurland. This prior art equipment is bulky, heavy, and cumbersome to use. The handling of weights can be hazardous and their mass requires very sturdy operating tables and other supporting jigs.
The instant invention results from an attempt to eliminate the use of weights-biased orthopedic traction devices.